Magnetic catch



United States Patent 3,039,803 MAGNETIC CATCH Milton Stoll and Mark Stoll, both of New York, N.Y., assignors to Do-Well Industries, Inc., New York, N.Y., a corporation Filed June 10, 1955, Ser. No. 514,459 9 Claims. (Cl. 292-2515) This invention relates generally to magnetic catches, such as a magnetic door catch; and one object of the invention is to provide a new and useful magnetic door catch comprising a housed permanent magnet, as one part thereof, and a cooperating keeper or armature as another part thereof.

When the invention is embodied as a magnetic door catch, as illustrated in the drawing, it is generally immaterial which part is mounted on the door and which part is mounted on the associated jamb; but it would appear preferable, in most cases, that the magnet be mounted on or near the jamb and that the keeper or annature be mounted on an edge of the door distant from the hinges thereof.

In a preferred construction of the housed permanent magnet shown herein the housing is a box-like structure of the fold-over type and is of nonmagnetic material, such as sheet aluminum, and with one side of the structure being open. Further, the housing is an elongated parallelepiped; and one side of the housing, say, for convenience, the bottom thereof or that side to be applied to the door or jamb is more or less centrally punched downwardly to provide a short sleeve into which a plug may be forced-fitted. One side of the housing adjacent that just described is open. At each longitudinal end of the housing is an ear, which is ofiset from the first described side so that the bottom of the ears and of the sleeve are coplanar. The ears are each provided with a round screw hole and a slot whereby some slight orientation of the housing with respect to the door or jarnb may be had in mounting the housing and its contents. The magnet structure within the housing comprises a sandwich of three elements, the middle one being a permanent magnet shaped somewhat like a thin brick and having a central bore therethrough connecting the two sides of greatest area, and the other two elements, on either side of the magnet, being relatively thin pole pieces of magnetizable but not permanently magnetized material. In the assembly the pole pieces, which are substantially as long as the permanent magnet but slightly wider, protrude through the opening of the housing, which is not necessarily true of the permanent magnet itself. Each pole piece in one embodiment of the invention is pro vided with a protuberance which is centered with respect to its longest dimension but not exactly with respect to its transverse dimension; and, in assembly, the pole pieces are other hand to each other so that these protuberances are received within the ends of the central bore of the permanent magnet. The thickness of the sandwich comprising the two pole pieces and the permanent magnet is just slightly less than the lower surface of what may be called the top of the housing and the upper surface of what has been earlier suggested as the bottom of the housing; and the length of the sandwich is almost, but not quite, the inside length of the housing. Registered with the protuberance of each pole piece is a depression. While the depression of what may be called the upper pole piece is not useful in the assembly, the depression of the opposite pole piece is, in that the aforementioned plug is received therein for preventing the sandwich from escaping from the housing, and permitting limited translatory movement of and within said sandwich within the limits of the tolerances of fit between plug and depression, corresponding protuberance and central bore of permanent magnet, central bore of permanent magnet and other protuberance in upper pole piece, and as a pivot on which the sandwich may rotate within limits predetermined by the end walls of the housing. The edges of the magnet and the pole pieces opposite the opening of the housing are normally in register but do not reach the wall of the housing at what may be called the rear thereof; and a bent leaf spring is inserted between such wall and the magnet and its pole pieces whereby the normal tendency of the sandwich is to align itself with the opening of the housing.

The keeper or armature is a block of magnet-izable material the thickness of which should proximate that of a pole piece, and a feature of the invention is that the keeper or armature may be mounted on the door or jamb, as desired, by a single screw, and prevented from rot-ating by relatively small cleats formed at the corners of the keeper or armature by bending such corners in a common direction out of the main plane of this part of the catch. Of course the length and breadth of the keeper or armature should be substantially equal to the magnetic sandwich, and mounted so as to register therewith when the door is in closed position.

It will be understood that the slight rotary and translatory motion available in the sandwich not only compensates for the rotary path followed by the closing door, but also compensates, within limits, for initial irregularities of the door and jamb structure and for such irregularities as may arise from use, such as springing or deformation of the hinges of the door.

Herein the invention is illustrated with the magnetic structure mounted proximate to the jamb and the keeper or armature mounted to mate with such structure, and, therefore, on what is the inside of the door when the same is in closed position.

These and other objects, features, and advantages of the invention will be more fully understood from the following description and from the drawing, wherein the catch is indicated as applied to a cabinet, all parts of the latter which are shown being in dotted lines. But it will also be understood that the invention is not limited to use with cabinets, as, for example, it may be employed as a magnetic door catch for, say, screen doors of porches, or as a magnetic catch for other uses.

In the drawing:

FIG. 1 is a plan view of the invention embodied as a magnetic door catch. The figure is partly in section to show certain internal parts.

FIG. 2 is an elevational view of the magnetic part of the catch, the keeper or armature being removed to show a housed magnetic sandwich comprising a permanent magnet with pole pieces on either side thereof. The figure is partly in section to show how the sandwich is mounted within a convenient housing.

FIG. 3 is an elevational end view of the catch as it would appear if viewed from the right in FIG. 1.

FIG. 4, much reduced, is a plan view of a blank from which a fold-over housing for the present housing may be made.

FIG. 5, much reduced, is a fragmentary front elevation of an alternative construction; and the angle of view corresponds to that of FIG. 2.

FIG. 6, also much reduced, is a fragmentary front elevation' of still another alternative construction and the angle of view corresponds to that of FIG. 2.

The housing, in its entirety, is designated 10 when completely formed, and may be made from a stamped blank 11 as shown in FIG. 4. The housing, as clearly seen in FIGS. 1, 2, and 3, is a box-like structure open on one side, and which side, for convenience herein, will be reture.

ferred to as the front. Referring to FIG. 2, which is a front elevational view of the entire magnetic part of the embodiment, it is seen that the bottom 12 of the box-like structure is mounted proximate to the jamb of what may be regarded as a cabinet. Indeed, the magnetic part of the embodiment may itself operate as the jamb. Here the magnetic part of the embodiment is mounted on the floor of the cabinet, a corner only of which is indicated, and that in dotted lines.

The housing is preferably of greatest dimension in parallelism with the jarnb or front edge of the opening of the cabinet (FIG. 1). The bottom 12 extends on either side of the box-like structure forming ears 13 and 14, as shown in FIGS. 1 and 2. In FIG. 1 it will be seen that each ear is provided with a screwhole and a slot. The screw hole of car 13 is indexed 15 and its associated slot 16; the screw whole 17 and slot 18 or ear 14 are reversed with respect to the equivalent apertures of car 13 (see FIG. 1). Accordingly, some slight adjustment of the alignment of the housing with respect to the front edge of the floor of the cabinet is possible. The housing is what is generally known as a foldover; and although the housing may be formed of a single stamped blank of suitable nonmagnetic metal (FIG. 4), various parts of the blank, before and after formation of the housing, are assigned special reference numerals. The top and sides of the housing, best seen in FIG. 2, are respectively designated 19, 20, and 21, while the back wall (FIGS. 1 and 3) is indexed 22.

In forming the housing from the blank 11 (FIG. 4) the portion thereof intended to become the bottom 12 is punched or otherwise perforated nearly in the center, and a dependent cylindrical sleeve results from this operation. Also the front marginal portion of bottom 12 is bent downwardly to form an apron. The apron is designated 23 and the sleeve 24 (see FIGS. 2 and 3). Those portions of the blank 11 intended to result in the ears 13 and 14 are offset downwardly from the bottom 12, as best seen in FIG. 2; and the lower surfaces of the ears 13 and 14, the apron 23, and the sleeve 24 are within a common plane in the finished housing. See FIG. 2.

Those portions of the blank 11 which are to form the sides and 21 of the housing are provided with ears 25, relatively much smaller than ears 13 and 14, which, in the finished housing, pass through slots 26 (see FIGS. 1 and 4) provided in bottom 12; and these cars may be slightly crimped or twisted in the nearly finished housing to prevent the fold-over structure from springing apart. See FIGS. 1, 3, and 4.

The magnet structure within the housing comprises a permanent magnet 27 having on the top and bottom thereof a pole piece. While the pole pieces are alike they are reversed with respect to each other in the general assembly, asbest shown in FIG. 2. The upper pole piece is designatedZ S, the lower 29. The length of the permanent magnet and of the pole pieces is substantially common; however, the width of the pole pieces is somewhat greater than that of the permanent magnet; and while the permanent magnet does not protrude through the opening. in the front of the housing, the front edges of the pole pieces do, as shown in FIG. 3.

The permanent magnet is boredfrom top to bottom at its center. Each pole piece is here shown to be a rectangular plate having, on one side, a round protuberance 30, which is centered longitudinally with respect to the has been remarked that the pole Pieces arereversed with respect to each other in the sandwich-like magnet struc- The round protuberance of pole piece 28 is re protuberance 30. A round plug 32, forced-fitted into sleeve 24, has its upper portion 33 extending freely into the recess 34 of the lower pole piece 29'. See FIG. 2. Since the aggregate height of the permanent magnet and the two pole pieces is but a trifle less than the inside height of the housing, the plug 32 operates as a key to prevent escape of the sandwich-like magnet structure from the housing. Also it will be seen in FIG. 1 that the length and breadth within the housing of the said magnet structure is somewhat less than the inside corresponding dimensions of the housing. Thus the plug 32 may serve as a pivot on which the magnet structure may rotate within limits predetermined by the inner dimensions of the housing and as a stop limiting the translatory movement of the lower pole piece.

Since some space exists between the rear edges of the permanent magnet and its pole pieces, as a structural unit, and the back wall 22 of the housing, a bowed or undulant leaf spring 35 may be placed within such space, if desired, for the purpose of urging the magnetic structure to seek, even in the absence of the keeper or armature, presently to be described, that orientation with respect to the housing indicated in FIG. 1.

In FIGS. l-3 stationary portions of the cabinet are in dexed 35. Portions of a flush door 37 are seen in FIGS. 1 and 3. In FIG. 1 the door 37 is shown both fully closed and nearly closed.

Mounted on the inside of the door and adapted to engage in register'with the magnet structure when the door is closed is a keeper or armature 38, shown in FIGS. 1 and 3. The keeper or armature is a quadrilateral block of permeable metal with slightly rounded corners (FIGS. 1 and 3); and at each corner the metal is slightly deformed to provide a small dog or cleat 39 which, in assembly, is disposed toward the inside surface of the door. In the center of the keeper or armature is a screwhole 40, coun tersunk to accommodate a fiat-he-ad screw 4-1, which is indicated in dotted lines in the drawin and is employed for securing the keeper or armature to the inside of the door. Before driving the flat-head screw fully into position the keeper or armature should be carefully oriented to register properly with the magnetic structure when the door is closed. Then, when the screw is driven fully into position, the dogs or cleats 39 bite into the material of the door and in consequence prevent the keeper or armature from rotary movement.

In solid lines in FIGS. 1 and 3 the keeper or armature is shown in perfect engagement with the magnetic structure, and in dotted lines in FIG. 1 the keeper or armature is indicated as just approaching or having just left perfect engagement with the magnetic structure.

If desired, as seen in FIG. 6, plug 32a may have an extended upper portion 33 to go through a hole 30a in pole piece 29a thus permitting the extended upper portion 33 to engage the hole in the magnet 27. Because the protuberance 30 on upper pole piece 28 also engages the hole in the magent, the sandwich-like magnet structure is locked against escape from the housing. Similarly, as

7 shown in FIG. 5 the extended'upper port-ion 33'can be ceived within the upper portion of the bore 31 of the permade to go through pole piece 29a, magnet 27 and upper polepiece 2811, when the upper pole piece is likewise provided with a hole similar to the hole 30a in pole piece 29a described above.

FIGURE 5, shows an alternative construction whereby a plug 42 passes through a perforation in one element of. the housing and perforations in both pole pieces and the magnet.

We claim:

1. A magnetic door catch comprising a housing with one side thereof open and having a perforated bottom which provides a dependent sleeve, with the top of the housing having an uninterrupted flat surface; downwardly offset extensions of said bottom on two opposite sides of said housing being provided with screw holes, the lower surfaces of said extensions being substantially coplanar with the lower end of said sleeve; a permanent magnet structure carried within said housing for limited rotary and translatory movement, said structure comprising a sandwich of three elements with the middle element being a perforated permanent magnet, and the other elements being pole pieces each having a protuberance on one side and a depression on the other side, with the protuber ance of each pole piece being received in one end of the perforation of said magnet; a plug force-fitted into said sleeve and being received within a depression in one pole piece opposite the protuberance thereof, the thickness of said structure being slightly less than the inside height of said housing whereby said structure is prevented from escaping due to said protuberances, perforation, plug, and depression, with said catch adapted to cooperate with an armature.

2. In apparatus of the class described, a housing having an open front and a bottom; a perforated permanent magnet sandwiched between two pole pieces, each pole piece having a protuberance received within one end of the perforation of said magnet, said magnet and said pole pieces being somewhat less both in length and width than the inside of said housing and therefore capable of limited rotary and translatory movement within said housing, with the aggregate height of said maget and said pole pieces being just less than that of the interior of said housing; and means on the bottom of said housing engaging the lower of said pole pieces for maintaining said magnet and said pole pieces within said housing, with said apparatus adapted to cooperate with an armature.

3. The combination of claim 2, wherein said pole pieces protrude through the open front of said housing.

4. The combination of claim 2, including resilient means within said housing and behind said magnet and said pole pieces for urging them outwardly with respect to said housing.

5. In apparatus of the class described, a housing having an open front and an upwardly extending post on the bottom thereof; a perforated permanent magnet sandwiched between two pole pieces, each of said pole pieces having a protuberance on one side received within an end portion of the perforation of said magnet and with at least one of said pole pieces having a depression on the side opposite the protuberance thereof and registered therewith, said magnet and said pole pieces being carried within said housing with said post received within the depression of one of said pole pieces.

6. A magnetic door catch comprising a housing having a perforated bottom with a dependent sleeve, an open side, and a top with an uninterrupted smooth surface; downwardly ofiset extensions of said bottom on opposite sides thereof, each extension being provided with a slot and a screw hole, the lower surfaces of said extensions being substantially coplanar with the lower end of said sleeve; a permanent magnet structure carried partly within said housing for limited rotary and translatory movement, said structure comprising a sandwich of three elements with the middle element being a perforated permanent magnet, and the other elements being pole pieces, one thereof having a protuberance received in one end of the perforation of said magnet, and the other thereof having a perforation; and a plug force fitted into said sleeve and freely passed through the perforation of the last described pole piece into the perforation of said magnet, all dimensions of said structure being less than the inside corresponding dimensions of said housing, with said structure adapted to cooperate with an armature.

7, A magnetic catch comprising a housing having a top and a bottom with one of the two last named elements being perforated, an open side, and at least one flange provided with an aperture for a screw; a permanent magnet structure carried and held partly within said housing, said structure comprising a sandwich of three elements with the middle element being a perforated permanent magnet, and the other elements being pole pieces, with one pole piece being perforated and being between said magnet and that one of said first named elements which is perforated, and with the other pole piece having a protuberance partly received within the perforation of said magnet; and a plug passed through the first named perforated element, the perforated pole piece, and received partly within said perforation of said magnet, with said structure adapted to cooperate with an armature.

8. A magnetic catch comprising a housing, means for securing said housing to a support, 'a permanent magnet structure within said housing and having a portion thereof extending outwardly therefrom, said magnet structure comprising three elements disposed as a sandwich, the middle element of said three elements being a perforated permanent magnet, the other elements of said three ele-.- ments being pole pieces, said pole pieces being provided with projections for engagement with said perforation in said magnet, at least one of said pole pieces being provided with a recess, means carried by said housing engaging the walls of said recess for retaining said magnet structure in said housing, said magnetic catch being adapted to cooperate with an armature.

9. A magnetic catch comprising a housing, means for securing said housing to a support, a permanent magnet structure within said housing, and having a portion thereof extending outwardly therefrom, said magnet structure comprising three elements disposed as a sandwich, the middle element of said three elements'being a perforated permanent magnet, the other elements of said three elements being pole pieces, at least one of said pole piecesbeing provided with a projection for engagement with the Wall of said perforation in said magnet, the other pole piece being provided with a perforation in register with said perforation in said magnet, means carried by said housing engaging the walls of said perforations in said pole piece and said magnet for retaining said magnet structure in said housing, said magnet catch being adapted to cooperate with an armature.

References Cited in the file of this patent UNITED STATES PATENTS 2,117,132 Baermann May 10, 1938 2,240,035 Catherall Apr. 29, 1941 2,701,158 Schmitt Feb. 1, 1955 2,770,759 Ahlgren Nov. 13, 1956 2,877,040 Curtiss et a1. Mar. 10, 1959 

